THE VF.RTEBRAL COLUMN 



4.3 



az 



h 



AM.NM.555l 



az 



Fig. 1 1. — Right aspect of cervical IX of Mono- 

 clonkts (Centrosaurus) nasicornus, J4 natural size. 

 az, anterior zygapophysis; h, capitular facet; /, neural 

 spine; /, tubercular facet. 



Fig. 12. — Right aspect of dorsal 11 of Mono- 

 clonius {Centrosaurus) nasicornus, }4 natural size. 

 az, anterior zygapophysis; az', anterior zygapophysis 

 of succeeding vertebra; d, diapophysis; h, capitular 

 facet; fz, posterior zygapophysis; /, neural spine; 

 /, tubercular facet. 



Dorsal VI 



(Fig. 13) 



This vertebra differs greatly from that figured by Hatcher as a posterior median dorsal vertebra 

 of M. crassus. The centrum has flattened articular faces but, viewed laterally, is deeply constricted 

 and in addition has deep pleurocoeles in the upper half of each side. The capitular facet is now on 



Y.P.M 2015 



az 



F, r . 1 3 Dorsal VI of Monoclones (Centrosaurus) fiexus. Anterior and right lateral views, 34 natural size, az, 



anterior zygapophysis; d, diapophysis; h, capitular facet; n, neural canal; f, pleurocoelc; fz, posterior zygapophysis; 

 s, neural spine; /, tubercular facet. 



